possible malware/virus? Out of my element- please help

So these are the things I'm noticing with the computer:

the background was completely black and will not change.

the bar at the bottom of the screen is unusually small.

it won't connect to wireless internet (I know wireless is working b/c it is connected to the wii), though the ethernet cable works fine.

Every time I click on a link, it transfers to a totally different website, and I have to click the back button to go to the website I originally wanted.

When I try to go to an anti-malware website, it says there is a problem connecting to the server

When I do finally succeed in downloading a malware program, it will not open or run under any circumstances, not even when saved to a flashdrive from another computer.

When I tried installing hijackthis, it said "Could not create key 'such and such' Verify that you have sufficient access to that key, or contact your support personnel."

I hope that is enough information, any help I can get is greatly appreciated! Thanks!

It seems that you are infected with the malware or the adware which is causing the issue with the system. I will advise you to install the Malware bytes on to the system and then try to run the full system scan for the infection. But make sure that you are updated with the latest virus definition. If the MalwareBytes is unable to update then it is better you should boot the computer into the Safe Mode with Networking. After that try to update and run the system scan for virus. To download the Malwarebytes' Anti-Malware you should visit this.